This invention relates generally to a rainwater collection and storage system, and more particularly to a gutterless rainwater harvesting and storage system which allows a controlled percentage of roof run-off to access, via designed slots in steel roof sheeting and a collection system, a series of narrow section (200 to 250 mm wide) tanks, which, in new building construction, can replace conventional solid external walls. The slots in the roof sheeting are dimensioned and shaped to allow optimum water entry, while excluding leaves and gum nuts.
Water tanks to store roof water are extremely well-known. It is well-known to provide a steel, or plastic, and a generally cylindrical, water tank next to a house with the gutters of the house being connected to the water tank inlet via a down pipe. It is known to have mesh screens or similar devices to keep leaves, twigs, and the like from entering the rainwater tank. These large cylindrical tanks are usually placed next to the house and on a support platform.
It is also known to have mini tanks (typically formed from plastic) positioned against a house wall and under the roof eaves. The mini tank can hold between 200 to 1000 litres of water and, as is common, has a lower tap. Again, a mesh screen and the like can be used to keep leaves and twigs from entering the mini tank. The mini tank is attached to the roof gutter via a down pipe.
One disadvantage with these existing tanks is that they collect water from the roof gutter. The roof gutter is usually clogged with leaves, twigs, dirt, dust and rotting material, and the sieves and screens are not able to remove anything other than the larger twigs and leaves. This means that water in the tank can still contain appreciable undesired residue. This can be alleviated by regular and thorough cleaning of the roof gutters, but this is a job which is not popular with most home owners, inter alia, for safety reasons.
In rural and bush environments, gutters can be a fire hazard through leaf build-up and it is not uncommon for houses in these areas to not have gutters and instead to allow water to fall straight off the edge of the roof. Another disadvantage with gutters is that leaf build-up in the gutters can cause flooding of the eaves through over topping. However, gutterless systems would prevent water from being collected for conventional cylindrical tanks or mini tanks.
Another disadvantage with conventional water tanks is that they are unsightly and are often in the way. While the mini tanks attempt to minimise this disadvantage, these tanks are still quite visible and noticeably bulge from a house wall.
Conventional water tanks are used only to collect and store water for drinking or irrigation purposes. To date, there has been no attempt to utilize the potential heat exchange properties of the water stored within the tank. If the tanks are placed in the sun, the water will slowly warm up, and in theory, can provide a good source of heat during the cooler periods at night. However, conventional tank designs do not take advantage of this property.
The present invention is directed to a rainwater collection and storage system which can collect and store rainwater without requiring the roof gutter. The invention is also directed to a climate management system for a building which uses a series of water tanks.
It is an object of the invention to provide a rainwater collection and storage system which may overcome the abovementioned disadvantages or provide the public with a useful or commercial choice.
In one form, the invention resides in a rainwater collection and storage system to collect and store roof water, the system comprising water collection slots extending through roof sheets and spaced from the edge of the roof, a manifold or other type of collection means below the roof sheets to collect the water from at least some of the slots, and at least one tank wall to store the collected water, the at least one tank wall having a narrow section to approximate a wall thickness, and typically extending from a ground floor to adjacent the roof.
In another form, the invention resides in a climate management system for a building which comprises a plurality of water tanks spaced about the building and either forming part of the external walls, or in front of the external walls, the water tanks being of narrow section to approximate a wall thickness, the tanks being interconnected by pipe work, pump means to pump water between the tanks, and temperature sensing means to sense the water temperature in the tanks, whereby water can be pumped between tanks to provide climate control to the building.
The rainwater collection and storage system collects water via slots extending through the roof sheeting and therefore does not require a gutter. This can provide cleaner and more hygienic water. The system can be used on roofs which are gutterless, for instance of houses in wooded areas where bush fires are a risk.
The roof sheets are typically metal profiled roof sheets as the collection slots are fairly easily punched or otherwise formed in the sheets. The collection slots are positioned to intercept the water running along at least some portion of the roof. It is envisaged that the slots can extend across the entire roof width, or along discrete portions or zones of the roof.
The collection slots are spaced from the edge of the roof. This may be in order to collect clean water, it being appreciated that at the edge of the roof there can be leaf, twig and other debris build-up. If the roof is supported by a wall, it is preferred that the slots are positioned to be substantially above the wall for reasons which will be described in greater detail below.
A number of collection slots may be provided and the size and shape of the collection slots can vary depending inter alia on the profile of the roof, and the typical annual rainfall in the region. The collection slots may be configured such that in heavy downpours, excess water simply bridges the slot gaps and runs off the edge of the roof. In low rainfall areas, more collection slots may be provided to catch as much water as possible. The shape and size of the slots is preferably such to allow optimum water entry while excluding leaves, twigs, gum nuts and the like.
In a preferred embodiment of the invention, the collection slots are located in roof insert members and the insert members may be mounted in receiver slots formed in the roof. Typically, the insert members are removably mounted in the receiver slots. An advantage of providing removable insert members is that the density, size and the like of the collection slots may easily be changed if desired by interchanging insert members having collection slots of different sizes etc. Insert members can also be replaced if damaged or irreversibly blocked by a twig or the like. This may be more cost effective than replacing a roof section. Insert members may also be interchanged to optimize rain water collection during dry or wet seasons. The profile (for instance corrugations) provides ridges and valleys with the valleys concentrating the water running off the roof sheets.
The roof insert member can be made from metal or ultra-violet stabilised plastics and comprises a shape consistent with the receiver slot in the roof sheeting surface. The insert member typically has first or upper end and a second or lower end, and in use the first end is located upstream from the second end relative to the normal direction of rainwater flow across the roof. Both ends of the roof insert members typically have a discrete shape so that they may be inserted in one direction only.
Typically, the upper end of the insert member contains a mouth-like slot which, in use, houses an edge of the roof sheeting receiver slot and positively locates the nose or upper end of the insert member. On the lower surface of the insert member at the lower or tail end of the insert member may be located a small tab depending therefrom. This tab typically includes a grippable portion to assist in manual removal of the insert member and may also act as a roofwater flow brake to assist flow capture by the insert member.
The lower surface of the insert member typically firmly or snuggly fits in the roof receiver slot. However, the insert members upper surface is typically dimensioned to be slightly larger than the receiver slot thus providing a substantially watertight fit and a support function around the margin of the insert member. Typically, the insert member has a lip extending along at least part of the upper surface and in use this lip overlaps the edge of the roofing sheet.
On the lower surface of the insert member at the bottom, or downstream, end is typically located a vertical deflector tab or fin which can direct any roofwater running on the lower side of the insert member down into the collection means. Part of this vertical defector fin may also contain an integral lever clip which positively locates the insert member in the receiver slot of the roof sheeting. Typically such a clip would be able to be compressed by thumb or finger pressure to enable the insert member to be unlocked, removed and replaced by another insert member suited to updated rainfall forecast trends.
By providing a number of interchangeable insert members containing varying numbers and patterns of collection slots, it is possible to provide suitable capacity to accept varying expected rainfall events determined by the geographical location and the seasonal characteristics of various localities. Such information is now provided by long range climate forecast units sponsored by government. Based on these climate forecasts, a house owner can easily replace the insert member with another set more suitably calibrated to the expected rainfall outlook.
Underneath the roofing sheets and below the collection slots is a collection means, typically in the form of a moulded box chamber. The box chamber which can be made from plastic collects the roofwater from at least some of the collection slots. If a width of roof is provided with an array of insert members, each box chamber located between the roof rafters may discharge into a manifold provided to collect the water passing through all the insert members and to pass the water into at least one tank wall.
The manifold can be in the form of a pipe underneath the box chambers to collect the water. A number of separate manifolds may be provided each collecting water from a zone or array of insert members and passing the water into the same or different tank wall modules.
The manifold may be connected to one or several box chambers which have a wider upper area immediately below the insert members and a lower narrower pipe area which connects with the manifold. A mesh or sieve can extend through the box chamber and between the insert members and the chamber neck to remove any debris which may pass through the insert member strainer surface.
On leaving the manifold and entering the tank wall unit, the initial contaminated roofwater containing dust and other organic matter typically flows into an integral and separate tank column located inside the tank wall module. Once this inner tank column is filled all other roof water flows into the main storage volume of the tank wall. The first flush water discharges through a dump valve at the base of the inner tank to waste.
Underneath the roofing sheets and below the collection slots is a collection means, typically in the form of a manifold. The manifold collects the water from at least some of the slots. If a width of roof is provided with an array of slots, a single manifold can be provided to collect the water passing is through all the slots and to pass the water into at least one tank wall. The manifold can be in the form of a gutter underneath the slots to collect the water. A number of separate manifolds may be provided each collecting water from a zone or array of slots and passing the water into the same or different tank walls.
The manifold may form the lower part of a collector box which has a wider upper area immediately below the water collection slots and a lower narrower gutter area which comprises the manifold. A mesh or sieve can extend through the collector box and between the slots and the manifold to remove any debris which may pass through the slots.
Between the manifold and the tank wall may be a first flush pipe valve which collects and disposes of the first quantity of water entering into the manifold, the first quantity often containing dust and debris. Once the initial contaminated water has been disposed of, the remaining water can enter into the inlet of the tank wall.
The tank wall is typically of a metal and/or plastic construction, and can replace conventional solid external walls. The section of the tank wall can be typical of an external wall which can be between 200 to 250 mm wide. The tank wall can extend from adjacent a ground floor to adjacent the roof. It is preferred that the tank wall is generally below the slots in the roof sheets. The tank wall can have a height of between 200 to 300 cm and a length which allows it to be positioned between load bearing posts or columns which support the roof structure. If the load bearing posts or columns are between 2 to 3 m apart, the tank wall can have a length of between 2 to 3 m to fit between the posts or columns.
The tank wall can be manufactured from steel such as coated corrugated steel with flat steel or moulded plastic ends, plastic such as food grade polyethylene, fibreglass or other materials.
The building can have an array of tank walls positioned between posts or columns and taking into account windows or doors. The tank walls can act as an efficient insulator against extremes of heat or cold, can provide a water supply for fire fighting, gardens, pools, or consumption.
If desired, the tank wall can be positioned below a window, and in this arrangement, the tank wall does not extend adjacent the roof but instead extends to below the bottom of the window. A suitable pipe can extend from the manifold to the tank wall.
The tank walls can provide a climate management system. For instance, the tank walls can be spaced about the walls of a house to absorb heat from a western wall in summer or a northern wall in winter (in the southern hemisphere). The tank walls can be interconnected by pipe work and a pump can be provided to pump water between the tanks. For instance, cooler water from the east side of the house can be pumped to a west facing tank to cool the west facing side of the house. In winter, warmer water can be distributed around the house from the north facing tank. A temperature sensing means can be provided to sense the water temperature in the tanks.
As well as providing a supply of water and climate control, the wall tanks also have good acoustic absorbing ability to reduce the noise levels from outside.